This invention relates to an adhesive tape and more particularly it describes a medical athletic adhesive tape. Some such prior art tape fabrics and backing materials have been constructed of spun warp yarns and a high number of spun filler yarns coated on one side with a primer and having an adhesive disposed thereon. Still other (U.S. Pat. No. 4,303,724) have been made from spun warp yarns and a low number of textured filler yarns having a plastic film backing attached thereto and an adhesive disposed thereon.
The aforementioned prior art athletic tape constructions were developed to give properties such as improved tear and adherence to the back surface of a tape when one layer of tape is crossed over another layer during an application.
Generally, an athletic tape should have properties such as: flexibility, conformability, and a significant reduction in blocking. For the purposes of this application, flexibility, conformability, and blocking are defined as follows: Flexability is demonstrated when a tape has excellent stretch capabilities in the crosswise direction which enable the tape to distort before wrinkling. Conformability is a tape, due to its stretchability, easily conforms to the various contours of the human body to which it is applied. Blocking is the adherence of material, such as tape, to itself and is referred to when material is wound upon itself, as is done in winding a roll of tape.
The aforementioned properties are essential qualities in an athletic adhesive tape and will be further discussed in subsequent paragraphs.
Some prior art attempts include U.S. Pat. No. 3,853,598 which discloses an adhesive tape composed of a closely woven high thread count synthetic fiber backing, coated on one side with a primer which bonds the fibers of the fabric together. Applied to the primer side of the fabric is an adhesive mass which is used to adhere the tape to the skin of the human body. It is stated in the patent that the adhesive mass does not enter into the synthetic fiber backing but only directly contacts the primer. Also, the fabric may be torn in either direction, and the fabric is said to provide excellent adherence to the back surface of a tape when one layer of tape crosses over a previously applied layer during an application.
There are several disadvantages associated with this prior art fabric. One disadvantage is that the fabric is a closely woven high thread count fabric. When a fabric has a high thread count and is closely woven, stiffness is inherently built into the fabric in the weaving process, thus making the fabric harsh, less flexible and less apt to conform to body members. As mentioned in an earlier paragraph, flexibility, and conformability are necessary requirements for a medical or athletic tape fabric. Users of such adhesive tape require a tape to be soft, flexible, and conformable so that when it is applied to a human body it will not be harsh against the skin and will follow the contours of any body member without wrinkling. Another disadvantage of this fabric is that it uses a primer as a base for the adhesive mass. To apply a primer to a fabric requires an additional step in the manufacturing process thus making this fabric more costly to manufacture than the present invention. One other disadvantage of this prior art fabric pertains to the adherence of one layer of tape to the other when they are crossed over each other. If the tape adheres to itself when crossed over itself in an application then it will adhere to itself when it is wound upon itself as when wound in a roll. The adherence or blocking of the tape to itself in a roll makes it very difficult to unwind and, therefore, is a constant irritation to personnel using the tape.
U.S. Pat. No. 4,303,724, of common assignee, discloses an adhesive duct tape for wrapping heating ducts comprising a layer of polyolefin film as a backing sheet with a reinforcing fabric containing textured yarn and having an adhesive disposed thereon. This patent is primarily concerned with the tear characteristics of the fabric but makes reference to some reduction in the amount of adhesive that has to be used on the fabric. The patent states that the textured yarns in the fabric allow said fabric to be torn in a smooth and even manner with a minimum amount of force being used.
A distinct disadvantage to this fabric is that it requires the use of a polyolefin film attached to the back surface of the fabric. By using a polyolefin film as a backing sheet in conjunction with the other components of the fabric, stiffness becomes inherently, and advantageously from this products viewpoint built into the fabric. The polyolefin backing film by itself may be considered pliable but once the composite of woven material, adhesive and plastic film are assembled together then the structure takes on different properties, such as stiffness. Stiffness, as discussed in an earlier paragraph, is an undesirable quality and unacceptable to persons who use tape. Another disadvantage related to the use of a backing film sheet is that the use of said film makes it necessary to have an additional step in the manufacturing process to laminate the film to the fabric thus adding to the cost of the fabric.
Thus, the prior art has made many attempts to provide an adhesive tape that would have properties such as flexibility, conformability, and essentially no blocking for wrapping peoples limbs, but has been unsuccessful in providing such a tape. Accordingly, the present invention utilizes less components than the prior art but provides an adhesive tape that is soft, flexible, and has conformability. The present invention also unexpectedly provided two additional benefits not found in the prior art. First, the degree of widthwise give of the fabric, or more specifically, the fabrics widthwise elongation was substantially improved. Second, a substantial reduction of blocking is achieved resulting in a tape that when rolled or wound onto itself and then unwound, does not adhere to itself.